Formed
at high pressures and low temperatures, especially in
low-grade regionally metamorphosed glaucophane schists;
formed from plagioclase during saussuritization of gabbros
and diabases; rarely in eclogites.

Lawsonite
is a very rare silicate mineral that is only found in
a few locations worldwide. Gems are extremely rare and
can be attractive with colorless, pale blue or pinkish
colors and strong dispersion.

The
main location for gem quality crystals is the type locality
at Reed Station, Tiburon Peninsula, Marin County, California,
USA. Other locations include Panoche Pass, San Benito County; in the Pacheco
Pass area, Santa Clara County, California, USA; Darrington,
Snohomish County, Washington, USA; the French and Italian
Alps; and near Tavsanh, Turkey.